1. Field of the Invention
The invention relates to a vehicular drive control apparatus provided with i) an electric differential portion that functions as an electric differential device and has a differential mechanism that distributes output from an engine to a first electric motor and a transmitting member, and a second electric motor that is connected to that transmitting member, and ii) a shifting portion that functions as an automatic transmission and constitutes part of a power transmitting path from the transmitting member to driving wheels. The invention also relates to a control method of a vehicular drive system. More particularly, the invention relates to improving torque response when the power transmitting path has been changed from a power transmission-interrupted state to a power transmittable state.
2. Description of the Related Art
Japanese Patent Application Publication No. 2005-351459 (JP-A-2005-351459), for example, describes a related control apparatus for a vehicular drive system that includes an electric differential portion and a shifting portion. The electric differential portion functions as an electric differential device and has a differential mechanism that distributes output from an engine to a first electric motor and a transmitting member, and a second electric motor that is connected to that transmitting member. The shifting portion functions as an automatic transmission and constitutes part of a power transmitting path from the transmitting member to driving wheels.
In JP-A-2005-351459, when the power transmitting path from the electric differential portion to the driving wheels is changed from a non drive state in which power is unable to be transmitted (such as when a shift lever is in the “N” position) to a drive state in which power is able to be transmitted (such as when the shift lever is in the “D” or “CR” position, for example), shift shock can be reduced, even if hydraulic pressure of friction apply elements of the shifting portion that change the power transmitting path to the power transmittable state is applied quickly, by synchronously controlling the rotation speed of the transmitting member to a rotation speed that corresponds to the input shaft of the shifting portion.
When the rotation speed of the transmitting portion is controlled to a completely synchronous speed, as in JP-A-2005-351459, the start and end of application of the friction apply element are unable to be determined from the change in the rotation speed of the transmitting member. Therefore, the apply timing is instead determined according to timer control. In this case, taking into account variation in the period of time that it takes for the apply element to apply, which varies according to the running state, and the like, of the vehicle, the timer period must be set longer, and as a result, the increase in drive torque (i.e., torque response) may be delayed.